How to Create Only One ggplot2 Legend in R (Example Code)

set.seed(876435)                           # Creating random data
my_df <- data.frame(x1 = rnorm(100),
                    x2 = rnorm(100),
                    my_shapes = letters[1:4],
                    my_colors = letters[1:4])
head(my_df)                                # Head of data
#            x1         x2 my_shapes my_colors
# 1  2.60613589  0.2015005         a         a
# 2  0.04928746  0.4702312         b         b
# 3  0.83441786  0.5546141         c         c
# 4 -0.06498267  1.2490154         d         d
# 5  1.75731612 -1.4194633         a         a
# 6  0.06409565  1.2595519         b         b

set.seed(876435) # Creating random data my_df <- data.frame(x1 = rnorm(100), x2 = rnorm(100), my_shapes = letters[1:4], my_colors = letters[1:4]) head(my_df) # Head of data # x1 x2 my_shapes my_colors # 1 2.60613589 0.2015005 a a # 2 0.04928746 0.4702312 b b # 3 0.83441786 0.5546141 c c # 4 -0.06498267 1.2490154 d d # 5 1.75731612 -1.4194633 a a # 6 0.06409565 1.2595519 b b

install.packages("ggplot2")                # Install ggplot2 package
library("ggplot2")                           # Load ggplot2

install.packages("ggplot2") # Install ggplot2 package library("ggplot2") # Load ggplot2

ggplot(my_df, aes(x = x1, y = x2,          # Creating ggplot2 graph
                  shape = my_shapes,
                  color = my_colors)) +
  geom_point()

ggplot(my_df, aes(x = x1, y = x2, # Creating ggplot2 graph shape = my_shapes, color = my_colors)) + geom_point()

ggplot(my_df, aes(x = x1, y = x2,          # Creating ggplot2 graph again
                  shape = my_shapes,
                  color = my_shapes)) +    # Redefine color
  geom_point()

ggplot(my_df, aes(x = x1, y = x2, # Creating ggplot2 graph again shape = my_shapes, color = my_shapes)) + # Redefine color geom_point()